A fuel cell has a stack structure in which a plurality of fuel cell units as power generation units are stacked, and includes terminal plates provided on the respective ends of the plurality of stacked fuel cell units to output the generated electric power to outside. A recently proposed technique employs a layered structure of a metal plate having corrosion resistance and a metal plate having good electrical conductivity for a terminal plate, in order to enhance the durability of the terminal plate as described in, for example, JP 2009-187729A.
In the terminal plate having the layered structure of different metal plates proposed in the above patent literature, not only the plate plane (surface) but the plate end face is coated with a corrosion-resistant conductive material layer, for example, a thermosetting resin mixed with electrically conductive metal powder. The plate end face is coated with the corrosion-resistant conductive material layer, and the terminal plate is fixed at its outer periphery. This may prevent misalignment between the plates due to different linear expansion coefficients of the respective plates and electrical corrosion at the contact faces of the respective plates.
The different metal plates constituting the terminal plate, however, have different linear expansion coefficients and have different degrees of expansion and contraction during power generation operation of the fuel cell. In the plate end face of the different metal plates, the corrosion-resistant conductive material layer bonded to the plate end face is repeatedly pushed and pulled, accompanied with expansion and contraction of the plates and may thus be deteriorated. The disclosure of the above literature does not fully consider the countermeasure against such expansion and contraction of the plates. There is accordingly still room for improvement of the durability of the terminal plate having the layered structure of different metal plates and the durability of the fuel cell. Other needs include a simple technique for improving the durability and reduction of the manufacturing cost of the fuel cell.
In order to solve at least part of the problems described above, the invention may be implemented by aspects described below.